Hydraulic compensating mechanism



H. E. VOORHIES HYDRAULIC COMPENSATING MECHANISM Filed April 15, 1948 as38 A 4o 48 4G 53' le 2?' /m ze 2 8 i 52 |530 l ZO INVENTOR. x3/ARMl/aoRH/fs a-Mab/Cyf@ A TTUR/VEVS Patented Oct. 17, 1950 ff UNITED ASTATES PATENT foFElcE HYDRAULIC coMifENsAfrING MEcHANlsM Harry E.Voorhies', Grosse Pointe'Woods, Mich.,

assgnorto Eaton Manufacturing Companys Cleveland, Ohio, v ar corporationof Ohio Y Application Apri`11v5, 1948. serial No;l 2:1,217

the poppet valves thereof in automatically compensating forl changes.`inthe operating lengthv of theS'yStem:

object of the invention is the provision of a simple and effectiveself-contained automatic compensating or adjusting hydraulic mechanism.AAnother object of the invention is the provision of a self-containedhydraulic ytappet 'or mechanism having the operating fluid thereforpermanently and hermetically sealed within the unit 'so' as to prohibitseepage of uid therefrom orfcontamination of the fluid with dustor-other foreign' substances from without the tappet. "Anoth'er objectof the invention is the provision of a. self-containedv'hydrauli-ctappet comprising a minimum number offparts forming" an economical andeilcient structure. `A further 'object of the invention is the provsionof an automatic compensating self-contained hydraulic tappet comprisinga tappet body, -a plunger reciprocable in the body having a valve Theautomatic adjusting mechanism herein devised is-specically in the formof a self-contained hydraulic tappet for use in the valve gear trainvof'internal combustion engines and comprises four major elements, acylindrical tappet body having a cavity therein closed at one end andopen at the other end, a plunger reciprocable therein having a valvecontrolled passage therethrough and forming in cooperation with theclosed end of the tappet body a hydraulic compression chamber, a capmember seated on one end of thel plunger and the combined flexiblediaphragm and sealing element xedly arranged at the cap end of theplunger of the open end of the tappet body forming a low pressure fluidfilled reservoir therewithin having communication with the compressionchamber by way of the passage therein, and a fluid sealing elementarrangedbef tween the plunger and body effectively 'sealing theoperatingnuid within the tappet and being eiective a'svthe tensile return meansfor extending the plunger relative to the body and for maintainingaslight pressure head on the supplyl of iluid in'the'reservoir when thetappet is subl jected tonorm'al operating conditions.

" Other objects and advantages of the invention will appear from thefollowing description taken ineconnection with the drawings, forming apart of the specication; and in which:

Fig; 1v is a vertical cross-sectional view' of a hydraulic compensatingself-contained hydraulic tappet;y I

Y Fig; 2 -is a vertical cross-sectional Aview of ."a

modiedY form of the tappet shown by Fig. 1; and

Fig. 3 is across-sectional view taken substantially along lines 3-3ofFig. 1. The present invention is directed at the provision of anautomatic compensating orA adjusting mechanism for usewith the valvegear train of internal combustionengines or the like for properlyv"adjusting theoperating length thereof,v

thatis simple and economical of construction and effectivefandecient inoperation.; l.. .1.' Y

in the plunger.

The combined flexible diaphragm sealing element serves the dual purposeof extension springs for normally biasing the plunger outwardlyrelativegto the tappet body and as an effectivesealingmeans'for'permanently and hermetically ysealingv the operatingfluid in the tappet body under all conditions of operation. By soproviding an automatic compensating mechanismy the selfcontained natureof the device adaptable to a variety of installations especially ininternal combustion engines without the requirement for engine designembodying hydraulic uid supply means.

`Reierring v to the drawings .for more specific details of theinvention, lll represents generally an automatic compensating mechanismin the form of a .tappet for use in a valve gear system of internalcombustion engines comprising a cylindrical tappet body l2 having acentral cavity M'therein closed at one end and open at rthe other endand having a cylindrical plunger I6 reciprocable therein and forming inconjunction with the tappet body a hydraulic compression chamber I8."V

- The tappet body yI 2 is'adapted to be received in a tappet guide, notshown, for movement therein and has integral therewith atits closed.end'a mushroom-shaped head 20 adapted to be engaged by'an engine cammember or the like, not shown. The plunger I6 includes a portion A22having 'a slightlysmaller'diameter than the diameter of the cavity l`4permitting of Va predetermined hy-k in the plunger communicating withpassage 26 and with compression chamber I8 by way of a relief passage 32formed in the plunger. The ball 28 is adapted to be retained in cavity30 through the cooperation of the plunger with the wall of the cavity I4in the tappet body thereby eliminating the necessity of any positiveretaining means normally incorporated in ball valve assemblies.

A cap member 34 is adapted to receive one end 36 of plunger I6 in pressfit relationship therein and includes an annular recess adapted toreceive one end 38 of a flexible sealing diaphragm 40 therebetween withend 36 of the plunger. The other end 42 of diaphragm 4I) is receivedinembracing relation between an annular recess V44 formed in the openend of tappet body I2 and an annular internal ring 46 mounted in. theopen end of the tappet body. The ring 46 in addition to effectivelysealing the end 42 of the diaphragm upon the tappet body is operative tolimitk the outward movement of the plunger-relative to the tappet body.The diaphragm 4B as arranged between the plunger and tappet bodyprovides areservoir chamber 43 about the reduced portion of the plungeradapted to communicate with the compression chamber I3 byway ofl passage26 provided in the plunger controlled as by ball valve 28.

The stiffness and resiliency of the diaphragm are predetermined so as toprovide. an effective tensile means operative to serve the purpose ofextending the plunger relative to the tappet body upon the requirementof an elongation of the tappet during the normal working operationthereof. If under certain conditions of operation the diaphragm is notsuitable to provide a sufliciently quick recovery for elongation of thetappet, spring means could be provided t assist Vthe diaphragm throughthe incorporation of the spring'means in association with or as a partof the diaphragm.

VIn the assembly of the tappet as a unit, the cavity in the tappet bodyis rst initially Alled with a suitable hydraulic fluid and then thecombined assembly of plunger I6, ball valve 28, cap 34, diaphragm 40,and ring 4S are inserted in and upon the tappet body with the end 42 ofthe diaphragm and ring 45 arranged in effective sealing relationin therecess of the tappet body and with the uid filling all the void spaceswithin the I tappet body, cap, and diaphragm ready for operational use.The compression and reservoir chambers together with the connectingpassages therebetween are adapted to be completely filled with iiuidsuch that in the normal vcondition of the tappet the diaphragm acts tobias the plunger outwardly from the tappet body a distance aspredetermined by the tensile strength and axial length of the diaphragm.

In a normal operation oi tappet Ic'when in installed position in thevalve vgearsystem of an internal combustion engine wherein 'the tappetis' set at its proper initial' length permitting 'of the extension andcontraction of the tappet within predetermined limits, and upon the`requirei ment for a contraction of the tappet because of .theaxialpressure being exerted `upon the tappet at the extremities thereof, thefluid .in the compression chamber leaks down along the wall'between theplunger and tappet body at a rate preyoperation of the tappet.

V4 assembled height in the gear train, the fluid in the reservoir isplaced under a slight pressure head because of the predeterminedstiffness of the diaphragm. As the fluid is transmitted to the lowpressure chamber or reservoir 48, the intermediate section of resilientdiaphragm 40 is moved radially outward providing the volumetric spacefor the displacement of the fluid transmitted thereinto. During thistransmission of the fluid to the reservoir and because of thepredetermined stiffness and resiliency of the diaphragm, the fluid inthe reservoir is placed under a slightly greater pressure than normaleffective to act upon the ball valve 28 thereby preloading the ballvalve from the reservoir for subsequent With the tappet in thebeforementioned position and upon the requirement for an extension ofthe tappet, the diaphragm in its capacity of a flexible tensile memberoperates to quickly and effectively move the plunger outwardly relativeto the tappet body assisted by the pressure of the fluid in thereservoir acting upon the valve to unset same and're-, plenish the fluidin the compression chamber upon ythe suction. created therein as theplunger moves in an extended direction relative to the tappet body.Thisoperation will continue until the vtappet has been extended therequired distance to Vtake up the clearance in the valve gear train soas to provide forv its subsequent, proper, effective, and quietoperation. This completes a normal cycle of extension and contraction ofthe tappet. v

Fig. 2 illustrates a modified form of automatic compensating devicewherein an intermediate or separate cylindrical body 56. is providedadapted to-be received in a tappet body 52. By incorporating a memberofthe structureof body 50 in the automatic compensating device per sereplacing body I 2 of Fig. 1, the operating unit is adaptable to varioussizes of tappet bodies per se or like operating mechanisms Vrequiringautomatic elongation and contraction. f

While this invention has been described in con- Vnection with certainspecific embodiments, the

principle involved is susceptible of numerous other applications thatwill readily occur to persons-skilled in the art. The invention,therefore, is limited only as indicated by the scope of the appendedclaims What I claim is: Y

1. A fiuid'self-contained length compensating mechanism comprising ahollow cylindrical body having closed and open ends and providing Vanannularrecess at its open end,'a plunger reciproe cable inthe cylinderhaving a portion fitted Vfor reciprocationl in the hollow of 'thecylinder and a reduced portion extending axially therefrom beyond theopen end of Athe cylinder, a cap press fitted von the end extremity ofthe reduced por-l tion of the plunger having 'an vannularrecess at itsopen' end :and vproviding invcooperation with the plunger an'annula'rgroove, an elastic sleeve diaphragm arranged in hermetically sealingrelation between the plunger and 'cylinder' having one annular endclamped 'in the vannular groove between the cap and'plunger and' itsother end tted in the annular "recess in the cylindensaid plungervproviding at one endl thereof With the closed'end of the cylinder vacompression chamber'andl with' the diaphragm-about' its reduced portion"a reservoir chamber andvalve means in the yplunger* 'providing one-waycoi'nrnunication between the reservoir `and compresSion"'t :ha1'r1`ber2. A fluid selfe'conta'ined length 4compensating mechanism comprising ahollow cylindrical body having closed and open ends and providing anannular recess at its open end, a plunger reciprocable in the cylinderhaving a portion tted for reciprocation in the hollow of the cylinderand a reduced portion extending axially therefrom beyond the open end ofthe cylinder, a cap press tted on the end extremity of the reducedportion of the plunger having an annular recess` at its open end andproviding in cooperation with the plunger an annular groove, an elasticsleeve diaphragm arranged in hermetically sealing relation between theplunger and cylinder having one annular end clamped in the annulargroove between the cap and plunger and its other end fitted in theannular recess in the cylinder, an annular ring mounted upon the end ofthe diaphragm tted in the annular recess in the cylinder clamping saidend in the annular recess, said plunger providing at one end thereofwith the closed end of the cylinder a compression chamber and with thediaphragm about its reduced portion a reservoir chamber and valve meansin the plunger providingV one-way cornmunication between the reservoirand compression chamber.

3. A fluid self-contained length compensating mechanism comprising ahollow cylindrical body having closed and open ends and providing anannular recess at its open end, a plunger reciprocable in the cylinderhaving a portion fitted for reciprocation in the hollow of the cylinder`and a reduced portion extending axiallyV therefrom beyond the open endof the cylinder, a cap press iitted on the end extremity of the reducedportion of the plunger having an annular recess at its open end andproviding in cooperation with the plunger an annular groove, an elasticsleeve diaphragm arranged in hermetically sealing relation between theplunger and cylinder having one annular end clamped in the annulargroove between the cap and plunger and its other end fitted in theannular recess in the cylinder, an annular ring mounted upon the end ofthe diaphragm iitted in the annular recess in the cylinder clamping saidend in the annular recess, said ring having an internal diameter that isless than the external diameter of the portion of the plungerreciprocable in the cylinder, said plunger providing at one end thereofwith the closed end of the cylinder a compression chamber and with thediaphragm about'l its reduced portion a reservoir chamber` and valvemeans in the plunger providing one-way communication between thereservoir and compression chamber.

4. A fluid self-contained length compensating mechanism comprising ahollow cylindrical body having closed and open ends and providing anannular recess at its open end, a plunger reciprocable inthe cylinderhaving a portion tted for reciprocation in the hollow of the cylinder, areduced intermediate portion and an enlarged head portion, a memberpress fitted on the head of the plunger having a portion thereofextending axially of the reduced portion of the plunger and providing incooperation therewith an annular groove, a flexible sleeve diaphragmarranged in hermetically sealing relation between the plunger andcylinder having one annular end clamped in the annular groove betweenthe cap and plunger and its other end iitted in the annular recess inthe cylinder, said plunger providing at one end thereof with the closedend of the cylinder acompression chamber and with the diaphragm aboutits reduced portion a reservoir chamber and valve means in the plungerproviding one-way communication between the reservoir and compressionchamber.

5. A claim according to claim 4 wherein an annular ring is mounted uponthe end of the diaphragm tte'd in the annular recess in the 'cylinderclamping said end in the annular recess.

HARRY E. VOORHIES. Y

REFERENCES CITED Y The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Loweke y Aug. 1, 1944

